Inbred maize line PH45A

ABSTRACT

An inbred maize line, designated PH45A, the plants and seeds of inbred maize line PH45A, methods for producing a maize plant, either inbred or hybrid, produced by crossing the inbred maize line PH45A with itself or with another maize plant, and hybrid maize seeds and plants produced by crossing the inbred line PH45A with another maize line or plant.

FIELD OF THE INVENTION

This invention is in the field of maize breeding, specifically relatingto an inbred maize line designated PH45A.

BACKGROUND OF THE INVENTION

The goal of plant breeding is to combine in a single variety or hybridvarious desirable traits. For field crops, these traits may includeresistance to diseases and is insects, tolerance to heat and drought,reducing the time to crop maturity, greater yield, and better agronomicquality. With mechanical harvesting of many crops, uniformity of plantcharacteristics such as germination and stand establishment, growthrate, maturity, and plant and ear height, is important.

Field crops are bred through techniques that take advantage of theplant's method of pollination. A plant is self-pollinated if pollen fromone flower is transferred to the same or another flower of the sameplant. A plant is cross-pollinated if the pollen comes from a flower ona different plant.

Plants that have been self-pollinated and selected for type for manygenerations become homozygous at almost all gene loci and produce auniform population of true breeding progeny. A cross between twodifferent homozygous lines produces a uniform population of hybridplants that may be heterozygous for many gene loci. A cross of twoplants each heterozygous at a number of gene loci will produce apopulation of hybrid plants that differ genetically and will not beuniform.

Maize (zea mays L.), often referred to as corn in the United States, canbe bred by both self-pollination and cross-pollination techniques. Maizehas separate male and female flowers on the same plant, located on thetassel and the ear, respectively. Natural pollination occurs in maizewhen wind blows pollen from the tassels to the silks that protrude fromthe tops of the ears.

A reliable method of controlling male fertility in plants offers theopportunity for improved plant breeding. This is especially true fordevelopment of maize hybrids, which relies upon some sort of malesterility system. There are several options for controlling malefertility available to breeders, such as: manual or mechanicalemasculation (or detasseling), cytoplasmic male sterility, genetic malesterility, gametocides and the like.

Hybrid maize seed is typically produced by a male sterility systemincorporating manual or mechanical detasseling. Alternate strips of twomaize inbreds are planted in a field, and the pollen-bearing tassels areremoved from one of the inbreds (female). Providing that there issufficient isolation from sources of foreign maize pollen, the ears ofthe detasseled inbred will be fertilized only from the other inbred(male), and the resulting seed is therefore hybrid and will form hybridplants.

The laborious, and occasionally unreliable, detasseling process can beavoided by using cytoplasmic male-sterile (CMS) inbreds. Plants of a CMSinbred are male sterile as a result of factors resulting from thecytoplasmic, as opposed to the nuclear, genome. Thus, thischaracteristic is inherited exclusively through the female parent inmaize plants, since only the female provides cytoplasm to the fertilizedseed. CMS plants are fertilized with pollen from another inbred that isnot male-sterile. Pollen from the second inbred may or may notcontribute genes that make the hybrid plants male-fertile. Seed fromdetasseled fertile maize and CMS produced seed of the same hybrid can beblended to insure that adequate pollen loads are available forfertilization when the hybrid plants are grown.

There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. Theseand all patents referred to are incorporated by reference. In additionto these methods, Albertsen et al., of Pioneer Hi-Bred, U.S. Pat. No.5,432,068, have developed a system of nuclear male sterility whichincludes: identifying a gene which is critical to male fertility;silencing this native gene which is critical to male fertility; removingthe native promoter from the essential male fertility gene and replacingit with an inducible promoter; inserting this genetically engineeredgene back into the plant; and thus creating a plant that is male sterilebecause the inducible promoter is not “on” resulting in the malefertility gene not being transcribed. Fertility is restored by inducing,or turning “on”, the promoter, which in turn allows the gene thatconfers male fertility to be transcribed.

There are many other methods of conferring genetic male sterility in theart, each with its own benefits and drawbacks. These methods use avariety of approaches such as delivering into the plant a gene encodinga cytotoxic substance associated with a male tissue specific promoter oran antisense system in which a gene critical to fertility is identifiedand an antisense to that gene is inserted in the plant (see:Fabinjanski, et al. EPO 89/3010153.8 publication no. 329,308 and PCTapplication PCT/CA90/00037 published as WO 90/08828).

Another system useful in controlling male sterility makes use ofgametocides. Gametocides are not a genetic system, but rather a topicalapplication of chemicals. These chemicals affect cells that are criticalto male fertility. The application of these chemicals affects fertilityin the plants only for the growing season in which the gametocide isapplied (see Carlson, Glenn R., U.S. Pat. No. 4,936,904). Application ofthe gametocide, timing of the application and genotype specificity oftenlimit the usefulness of the approach.

Development of Maize Inbred Lines

The use of male sterile inbreds is but one factor in the production ofmaize hybrids. The development of maize hybrids requires, in general,the development of homozygous inbred lines, the crossing of these lines,and the evaluation of the crosses. Pedigree breeding and recurrentselection breeding methods are used to develop inbred lines frombreeding populations. Breeding programs combine the genetic backgroundsfrom two or more inbred lines or various other germplasm sources intobreeding pools from which new inbred lines are developed by selfing andselection of desired phenotypes. The new inbreds are crossed with otherinbred lines and the hybrids from these crosses are evaluated todetermine which of those have commercial potential. Plant breeding andhybrid development are expensive and time consuming processes.

Pedigree breeding starts with the crossing of two genotypes, each ofwhich may have one or more desirable characteristics that is lacking inthe other or which complements the other. If the two original parents donot provide all the desired characteristics, other sources can beincluded in the breeding population. In the pedigree method, superiorplants are selfed and selected in successive generations. In thesucceeding generations the heterozygous condition gives way tohomogeneous lines as a result of self-pollination and selection.Typically in the pedigree method of breeding five or more generations ofselfing and selection is practiced: F₁→F₂; F₂→F₃; F₃→F₄; F₄→F₅, etc.

Recurrent selection breeding, backcrossing for example, can be used toimprove inbred lines and a hybrid which is made using those inbreds.Backcrossing can be used to transfer a specific desirable trait from oneinbred or source to an inbred that lacks that trait. This can beaccomplished, for example, by first crossing a superior inbred(recurrent parent) to a donor inbred (non-recurrent parent), thatcarries the appropriate gene(s) for the trait in question. The progenyof this cross is then mated back to the superior recurrent parentfollowed by selection in the resultant progeny for the desired trait tobe transferred from the non-recurrent parent. After five or morebackcross generations with selection for the desired trait and for thegermplasm inherited from the recurrent parent, the progeny will behomozygous for loci controlling the characteristic being transferred,but will be like the superior parent for essentially all other genes.The last backcross generation is then selfed to give pure breedingprogeny for the gene(s) being transferred. A hybrid developed frominbreds containing the transferred gene(s) is essentially the same as ahybrid developed from the same inbreds without the transferred gene(s).

Elite inbred lines, that is, pure breeding, homozygous inbred lines, canalso be used as starting materials for breeding or source populationsfrom which to develop other inbred lines. These inbred lines derivedfrom elite inbred lines can be developed using the pedigree breeding andrecurrent selection breeding methods described earlier.

Development of Maize Hybrids

A single cross maize hybrid results from the cross of two inbred lines,each of which has a genotype that complements the genotype of the other.The hybrid progeny of the first generation is designated F₁. In thedevelopment of commercial hybrids only the F₁ hybrid plants are sought.Preferred F₁ hybrids are more vigorous than their inbred parents. Thishybrid vigor, or heterosis, can be manifested in many polygenic traits,including increased vegetative growth and increased yield.

The development of a maize hybrid involves three steps: (1) theselection of plants from various germplasm pools for initial breedingcrosses; (2) the selfing of the selected plants from the breedingcrosses for several generations to produce a series of inbred lines,which, although different from each other, breed true and are highlyuniform; and (3) crossing the selected inbred lines with differentinbred lines to produce the hybrid progeny (F₁). During the inbreedingprocess in maize, the vigor of the lines decreases. Vigor is restoredwhen two different inbred lines are crossed to produce the hybridprogeny (F₁). An important consequence of the homozygosity andhomogeneity of the inbred lines is that the hybrid between a definedpair of inbreds will always be the same. Once the inbreds that give asuperior hybrid have been identified, the hybrid seed can be reproducedindefinitely as long as the homogeneity of the inbred parents ismaintained.

A single cross hybrid is produced when two inbred lines are crossed toproduce the F₁ progeny. A double cross hybrid is produced from fourinbred lines crossed in pairs (A×B and C×D) and then the two F₁ hybridsare crossed again (A×B)×(C×D). Much of the hybrid vigor exhibited by F₁hybrids is lost in the next generation (F₂). Consequently, seed fromhybrids is not used for planting stock.

Hybrid seed production requires elimination or inactivation of pollenproduced by the female parent. Incomplete removal or inactivation of thepollen provides the potential for self pollination. This inadvertentlyself pollinated seed may be unintentionally harvested and packaged withhybrid seed.

Once the seed is planted, it is possible to identify and select theseself pollinated plants. These self pollinated plants will be geneticallyequivalent to the female inbred line used to produce the hybrid.

Typically these self pollinated plants can be identified and selecteddue to their decreased vigor. Female selfs are identified by their lessvigorous appearance for vegetative and/or reproductive characteristics,including shorter plant height, small ear size, ear and kernel shape,cob color, or other characteristics.

Identification of these self-pollinated lines can also be accomplishedthrough molecular marker analyses. See, “The Identification of FemaleSelfs in Hybrid Maize: A Comparison Using Electrophoresis andMorphology”, Smith, J. S. C. and Wych, R. D., Seed Science andTechnology 14, pp. 1-8 (1995), the disclosure of which is expresslyincorporated herein by reference. Through these technologies, thehomozygosity of the self pollinated line can be verified by analyzingallelic composition at various loci along the genome. Those methodsallow for rapid identification of the invention disclosed herein. Seealso, “Identification of Atypical Plants in Hybrid Maize Seed byPostcontrol and Electrophoresis” Sarca, V. et al., Probleme de GeneticaTeoritica si Aplicata Vol. 20 (1) p. 29-42.

As is readily apparent to one skilled in the art, the foregoing are onlysome of the various ways by which the inbred can be obtained by thoselooking to use the germplasm. Other means are available, and the aboveexamples are illustrative only.

Maize is an important and valuable field crop. Thus, a continuing goalof plant breeders is to develop high-yielding maize hybrids that areagronomically sound based on stable inbred lines. The reasons for thisgoal are obvious: to maximize the amount of grain produced with theinputs used and minimize susceptibility of the crop to pests andenvironmental stresses. To accomplish this goal, the maize breeder mustselect and develop superior inbred parental lines for producing hybrids.This requires identification and selection of genetically uniqueindividuals that occur in a segregating population. The segregatingpopulation is the result of a combination of crossover events plus theindependent assortment of specific combinations of alleles at many geneloci that results in specific genotypes. The probability of selectingany one individual with a specific genotype from a breeding cross isinfinitesimal due to the large number of segregating genes and theunlimited recombinations of these genes, some of which may be closelylinked. However, the genetic variation among individual progeny of abreeding cross allows for the identification of rare and valuable newgenotypes. These new genotypes are neither predictable nor incrementalin value, but rather the result of manifested genetic variation combinedwith selection methods, environments and the actions of the breeder.

Thus, even if the entire genotypes of the parents of the breeding crosswere characterized and a desired genotype known, only a few if anyindividuals having the desired genotype may be found in a largesegregating F₂ population. Typically, however, neither the genotypes ofthe breeding cross parents nor the desired genotype to be selected isknown in any detail. In addition to the preceding problem, it is notknown how the genotype would react with the environment. This genotypeby environment interaction is an important, yet unpredictable, factor inplant breeding. A breeder of ordinary skill in the art cannot predictthe genotype, how that genotype will interact with various climaticconditions or the resulting phenotypes of the developing lines, exceptperhaps in a very broad and general fashion. A breeder of ordinary skillin the art would also be unable to recreate the same line twice from thevery same original parents as the breeder is unable to direct how thegenomes combine or how they will interact with the environmentalconditions. This unpredictability results in the expenditure of largeamounts of research resources in the development of a superior new maizeinbred line.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel inbred maize line,designated PH45A. This invention thus relates to the seeds of inbredmaize line PH45A, to the plants of inbred maize line PH45A, to methodsfor producing a maize plant produced by crossing the inbred maize linePH45A with itself or another maize line, and to methods for producing amaize plant containing in its genetic material one or more transgenesand to the transgenic maize plants produced by that method. Thisinvention also relates to methods for producing other inbred maize linesderived from inbred maize line PH45A and to the inbred maize linesderived by the use of those methods. This invention further relates tohybrid maize seeds and plants produced by crossing the inbred line PH45Awith another maize line.

DEFINITIONS

In the description and examples that follow, a number of terms are usedherein. In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided. NOTE: ABS is in absolute termsand %MN is percent of the mean for the experiments in which the inbredor hybrid was grown. These designators will follow the descriptors todenote how the values are to be interpreted. Below are the descriptorsused in the data tables included herein.

ANT ROT=ANTHRACNOSE STALK ROT (Colletotrichum graminicola). A 1 to 9visual rating indicating the resistance to Anthracnose Stalk Rot. Ahigher score indicates a higher resistance.

BAR PLT=BARREN PLANTS. The percent of plants per plot that were notbarren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near thetime of pollination, and is an indication of whether a hybrid or inbredwould snap or break near the time of flowering under severe winds. Dataare presented as percentage of plants that did not snap.

BU ACR=YIELD (BUSHELS/ACRE). Yield of the grain at harvest in bushelsper acre adjusted to 15.5% moisture.

CLD TST=COLD TEST. The percent of plants that germinate under cold testconditions.

CLN=CORN LETHAL NECROSIS. Synergistic interaction of maize chloroticmottle virus (MCMV) in combination with either maize dwarf mosaic virus(MDMV-A or MDMV-B) or wheat streak mosaic virus (WSMV). A 1 to 9 visualrating indicating the resistance to Corn Lethal Necrosis. A higher scoreindicates a higher resistance.

COM RST=COMMON RUST (Puccinia sorghi). A 1 to 9 visual rating indicatingthe resistance to Common Rust. A higher score indicates a higherresistance.

D/D=DRYDOWN. This represents the relative rate at which a hybrid willreach acceptable harvest moisture compared to other hybrids on a 1-9rating scale. A high score indicates a hybrid that dries relatively fastwhile a low score indicates a hybrid that dries slowly.

DIP ERS=DIPLODIA EAR MOLD SCORES (Diplodia maydis and Diplodiamacrospora). A 1 to 9 visual rating indicating the resistance toDiplodia Ear Mold. A higher score indicates a higher resistance.

DRP EAR=DROPPED EARS. A measure of the number of dropped ears per plotand represents the percentage of plants that did not drop ears prior toharvest.

D/T=DROUGHT TOLERANCE. This represents a 1-9 rating for droughttolerance, and is based on data obtained under stress conditions. A highscore indicates good drought tolerance and a low score indicates poordrought tolerance.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to thehighest placed developed ear node attachment and is measured in inches.

EAR MLD=General Ear Mold. Visual rating (1-9 score) where a “1” is verysusceptible and a “9” is very resistant. This is based on overall ratingfor ear mold of mature ears without determining the specific moldorganism, and may not be predictive for a specific ear mold.

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher therating the larger the ear size.

ECB 1LF=EUROPEAN CORN BORER FIRST GENERATION LEAF FEEDING (Ostrinianubilalis). A 1 to 9 visual rating indicating the resistance topreflowering leaf feeding by first generation European Corn Borer. Ahigher score indicates a higher resistance.

ECB 21T=EUROPEAN CORN BORER SECOND GENERATION INCHES OF TUNNELING(Ostrinia nubilalis). Average inches of tunneling per plant in thestalk.

ECB 2SC=EUROPEAN CORN BORER SECOND GENERATION (Ostrinia nubilalis). A 1to 9 visual rating indicating post flowering degree of stalk breakageand other evidence of feeding by European Corn Borer, Second Generation.A higher score indicates a higher resistance.

ECB DPE=EUROPEAN CORN BORER DROPPED EARS (Ostrinia nubilalis). Droppedears due to European Corn Borer. Percentage of plants that did not dropears under second generation corn borer infestation.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishmentin the spring and represents the number of plants that emerge on perplot basis for the inbred or hybrid.

EYE SPT=Eye Spot (Kabatiella zeae or Aureobasidium zeae). A 1 to 9visual rating indicating the resistance to Eye Spot. A higher scoreindicates a higher resistance.

FUS ERS=FUSARIUM EAR ROT SCORE (Fusarium moniliforme or Fusariumsubglutinans). A 1 to 9 visual rating indicating the resistance toFusarium ear rot. A higher score indicates a higher resistance.

GDU=Growing Degree Units. Using the Barger Heat Unit Theory, whichassumes that maize growth occurs in the temperature range 50° F.-86° F.and that temperatures outside this range slow down growth; the maximumdaily heat unit accumulation is 36 and the minimum daily heat unitaccumulation is 0. The seasonal accumulation of GDU is a major factor indetermining maturity zones.

GDU SHD=GDU TO SHED. The number of growing degree units (GDUs) or heatunits required for an inbred line or hybrid to have approximately 50percent of the plants shedding pollen and is measured from the time ofplanting. Growing degree units are calculated by the Barger Method,where the heat units for a 24-hour period are:${GDU} = {\frac{\left( {{Max}.\quad {temp}.\quad {+ \quad {{Min}.\quad {temp}.}}} \right)}{2} - 50}$

The highest maximum temperature used is 86° F. and the lowest minimumtemperature used is 50° F. For each inbred or hybrid it takes a certainnumber of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for aninbred line or hybrid to have approximately 50 percent of the plantswith silk emergence from time of planting. Growing degree units arecalculated by the Barger Method as given in GDU SHD definition.

GIB ERS=GIBBERELLA EAR ROT (PINK MOLD) (Gibberella zeae). A 1 to 9visual rating indicating the resistance to Gibberella Ear Rot. A higherscore indicates a higher resistance.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis). A 1 to 9 visual ratingindicating the resistance to Gray Leaf Spot. A higher score indicates ahigher resistance.

GOS WLT=Goss' Wilt (Corynebacterium nebraskense). A 1 to 9 visual ratingindicating the resistance to Goss' Wilt. A higher score indicates ahigher resistance.

GRN APP=GRAIN APPEARANCE. This is a 1 to 9 rating for the generalappearance of the shelled grain as it is harvested based on such factorsas the color of harvested grain, any mold on the grain, and any crackedgrain. High scores indicate good grain quality.

H/POP=YIELD AT HIGH DENSITY. Yield ability at relatively high plantdensities on 1-9 relative rating system with a higher number indicatingthe hybrid responds well to high plant densities for yield relative toother hybrids. A 1, 5, and 9 would represent very poor, average, andvery good yield response, respectively, to increased plant density.

HC BLT=HELMINTHOSPORIUM CARBONUM LEAF BLIGHT (Helminthosporiumcarbonum). A 1 to 9 visual rating indicating the resistance toHelminthosporium infection. A higher score indicates a higherresistance.

HD SMT=HEAD SMUT (Sphacelotheca reiliana). This score indicates thepercentage of plants not infected.

INC D/A=GROSS INCOME (DOLLARS PER ACRE). Relative income per acreassuming drying costs of two cents per point above 15.5 percent harvestmoisture and current market price per bushel.

INCOME/ACRE. Income advantage of hybrid to be patented over other hybridon per acre basis.

INC ADV=GROSS INCOME ADVANTAGE. GROSS INCOME advantage of variety #1over variety #2.

KSZ DCD=KERNEL SIZE DISCARD. The percent of discard seed; calculated asthe sum of discarded tip kernels and extra large kernels.

L/POP=YIELD AT LOW DENSITY. Yield ability at relatively low plantdensities on a 1-9 relative system with a higher number indicating thehybrid responds well to low plant densities for yield relative to otherhybrids. A 1, 5, and 9 would represent very poor, average, and very goodyield response, respectively, to low plant density.

MDM CPX=MAIZE DWARF MOSAIC COMPLEX (MDMV=Maize Dwarf Mosaic Virus andMCDV=Maize Chlorotic Dwarf Virus). A 1 to 9 visual rating indicating theresistance to Maize Dwarf Mosaic Complex. A higher score indicates ahigher resistance.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture ofthe grain at harvest.

MST ADV=MOISTURE ADVANTAGE. The moisture advantage of variety #1 overvariety #2 as calculated by: MOISTURE of variety #2−MOISTURE of variety#1=MOISTURE ADVANTAGE of variety #1.

NLF BLT=Northern Leaf Blight (Helminthosporium turcicum or Exserohilumturcicum). A 1 to 9 visual rating indicating the resistance to NorthernLeaf Blight. A higher score indicates a higher resistance.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant fromthe ground to the tip of the tassel in inches.

POL SC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount ofpollen shed. The higher the score the more pollen shed.

POL WT=POLLEN WEIGHT. This is calculated by dry weight of tasselscollected as shedding commences minus dry weight from similar tasselsharvested after shedding is complete.

POP K/A=PLANT POPULATIONS. Measured as 1000s per acre.

POP ADV=PLANT POPULATION ADVANTAGE. The plant population advantage ofvariety #1 over variety #2 as calculated by PLANT POPULATION of variety#2−PLANT POPULATION of variety #1=PLANT POPULATION ADVANTAGE of variety#1.

PRM=PREDICTED RELATIVE MATURITY. This trait, predicted relativematurity, is based on the harvest moisture of the grain. The relativematurity rating is based on a known set of checks and utilizes standardlinear regression analyses and is also referred to as the ComparativeRelative Maturity Rating System that is similar to the MinnesotaRelative Maturity Rating System.

PRM SHD=A relative measure of the growing degree units (GDU) required toreach 50% pollen shed. Relative values are predicted values from thelinear regression of observed GDU's on relative maturity of commercialchecks.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that donot root lodge; plants that lean from the vertical axis at anapproximately 30° angle or greater would be counted as root lodged.

RTL ADV=ROOT LODGING ADVANTAGE. The root lodging advantage of variety #1over variety #2.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount ofscatter grain (lack of pollination or kernel abortion) on the ear. Thehigher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amountof vegetative growth after emergence at the seedling stage(approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure ofthe hybrid's worth based on information for up to five traits. A maizebreeder may utilize his or her own set of traits for the selectionindex. One of the traits that is almost always included is yield. Theselection index data presented in the tables represent the mean valueaveraged across testing stations.

SLF BLT=SOUTHERN LEAF BLIGHT (Helminthosporium maydis or Bipolarismaydis). A 1 to 9 visual rating indicating the resistance to SouthernLeaf Blight. A higher score indicates a higher resistance.

SOU RST=SOUTHERN RUST (Puccinia polysora). A 1 to 9 visual ratingindicating the resistance to Southern Rust. A higher score indicates ahigher resistance.

STA GRN=STAY GREEN. Stay green is the measure of plant health near thetime of black layer formation (physiological maturity). A high scoreindicates better late-season plant health.

STD ADV=STALK STANDING ADVANTAGE. The advantage of variety #1 overvariety #2 for the trait STK CNT.

STK CNT=NUMBER OF PLANTS. This is the final stand or number of plantsper plot.

STK LDG=STALK LODGING. This is the percentage of plants that did notstalk lodge (stalk breakage) as measured by either natural lodging orpushing the stalks and determining the percentage of plants that breakbelow the ear.

STW WLT=Stewart's Wilt (Erwinia stewartii). A 1 to 9 visual ratingindicating the resistance to Stewart's Wilt. A higher score indicates ahigher resistance.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure thedegree of blasting (necrosis due to heat stress) of the tassel at thetime of flowering. A 1 would indicate a very high level of blasting attime of flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate therelative size of the tassel. The higher the rating the larger thetassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams)just prior to pollen shed.

TEX EAR=EAR TEXTURE. A I to 9 visual rating was used to indicate therelative hardness (smoothness of crown) of mature grain. A 1 would bevery soft (extreme dent) while a 9 would be very hard (flinty or verysmooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that couldpossibly shed pollen was taken. Data are given as a percentage oftillers: number of tillers per plot divided by number of plants perplot.

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grainin pounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain inpounds for a given volume (bushel) adjusted for 15.5 percent moisture.

TSW ADV=TEST WEIGHT ADVANTAGE. The test weight advantage of variety #1over variety #2.

WIN M %=PERCENT MOISTURE WINS.

WIN Y %=PERCENT YIELD WINS.

YLD=YIELD. It is the same as BU ACR ABS.

YLD ADV=YIELD ADVANTAGE. The yield advantage of variety #1 over variety#2 as calculated by: YIELD of variety #1−YIELD variety #2=yieldadvantage of variety #1.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relativerating for yield based on plot ear piles. The higher the rating thegreater visual yield appearance.

DETAILED DESCRIPTION OF THE INVENTION

Inbred maize lines are typically developed for use in the production ofhybrid maize lines. Inbred maize lines need to be highly homogeneous,homozygous and reproducible to be useful as parents of commercialhybrids. There are many analytical methods available to determine thehomozygotic and phenotypic stability of these inbred lines.

The oldest and most traditional method of analysis is the observation ofphenotypic traits. The data is usually collected in field experimentsover the life of the maize plants to be examined. Phenotypiccharacteristics most often observed are for traits associated with plantmorphology, ear and kernel morphology, insect and disease resistance,maturity, and yield.

In addition to phenotypic observations, the genotype of a plant can alsobe examined. There are many laboratory-based techniques available forthe analysis, comparison and characterization of plant genotype; amongthese are Isozyme Electrophoresis, Restriction Fragment LengthPolymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs),Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNA AmplificationFingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs),Amplified Fragment Length Polymorphisms (AFLPs), and Simple SequenceRepeats (SSRs) which are also referred to as Microsatellites.

The most widely used of these laboratory techniques are IsozymeElectrophoresis and RFLPs as discussed in Lee, M., “Inbred Lines ofMaize and Their Molecular Markers,” The Maize Handbook,(Springer-Verlag, New York, Inc. 1994, at 423-432) incorporated hereinby reference. Isozyme Electrophoresis is a useful tool in determininggenetic composition, although it has relatively low number of availablemarkers and the low number of allelic variants among maize inbreds.RFLPs have the advantage of revealing an exceptionally high degree ofallelic variation in maize and the number of available markers is almostlimitless.

Maize RFLP linkage maps have been rapidly constructed and widelyimplemented in genetic studies. One such study is described inBoppenmaier, et al., “Comparisons among strains of inbreds for RFLPs”,Maize Genetics Cooperative Newsletter, 65:1991, pg. 90, is incorporatedherein by reference. This study used 101 RFLP markers to analyze thepatterns of 2 to 3 different deposits each of five different inbredlines. The inbred lines had been selfed from 9 to 12 times before beingadopted into 2 to 3 different breeding programs. It was results fromthese 2 to 3 different breeding programs that supplied the differentdeposits for analysis. These five lines were maintained in the separatebreeding programs by selfing or sibbing and rogueing off-type plants foran additional one to eight generations. After the RFLP analysis wascompleted, it was determined the five lines showed 0-2% residualheterozygosity. Although this was a relatively small study, it can beseen using RFLPs that the lines had been highly homozygous prior to theseparate strain maintenance.

Inbred maize line PH45A is a yellow, dent maize inbred that is suited asa female for producing first generation F1 maize hybrids. Inbred maizeline PH45A is best adapted to the Central Corn Belt, Northwest,Northcentral and Northeast regions of the United States and can be usedto produce hybrids from approximately 97 relative maturity based on theComparative Relative Maturity Rating System for harvest moisture ofgrain. Inbred maize line PH45A demonstrates early flowering and goodstay green as an inbred per se. Inbred maize line PH45A can be used as afemale parent in hybrid production and in hybrid combination, PH45Ademonstrates good yields and early flowering for its maturity.

The inbred has shown uniformity and stability within the limits ofenvironmental influence for all the traits as described in the VarietyDescription Information (Table 1) that follows. The inbred has beenself-pollinated and ear-rowed a sufficient number of generations withcareful attention paid to uniformity of plant type to ensure thehomozygosity and phenotypic stability necessary to use in commercialproduction. The line has been increased both by hand and in isolatedfields with continued observation for uniformity. No variant traits havebeen observed or are expected in PH45A.

Inbred maize line PH45A, being substantially homozygous, can bereproduced by planting seeds of the line, growing the resulting maizeplants under self-pollinating or sib-pollinating conditions withadequate isolation, and harvesting the resulting seed, using techniquesfamiliar to the agricultural arts.

TABLE 1 VARIETY DESCRIPTION INFORMATION VARIETY = PH45A 1. TYPE:(describe intermediate types in Comments section): 2 1 = Sweet 2 = Dent3 = Flint 4 = Flour 5 = Pop 6 = Ornamental 2. MATURITY: DAYS HEAT UNITS066 1,149.0 From emergence to 50% of plants in silk 067 1,174.0 Fromemergence to 50% of plants in pollen 002 0,053.5 From 10% to 90% pollenshed 066 1,310.0 From 50% silk to harvest at 25% moisture 3. PLANT:Standard Sample Deviation Size 0,196.8 cm Plant Height (to tassel tip)15.67  4 0,073.3 cm Ear Height (to base of top ear node) 9.25  4 0,014.4cm Length of Top Ear Internode 1.11 20 0.0 Average Number of Tillers0.01  4 1.0 Average Number of Ears per Stalk 0.00  3 2.0 Anthocyanin ofBrace Roots: 1 = Absent 2 = Faint 3 = Moderate 4 = Dark 4. LEAF:Standard Sample Deviation Size 009.6 cm Width of Ear Node Leaf 0.91 20068.5 cm Length of Ear Node Leaf 4.10 20 05.1 Number of leaves above topear 0.77 20 045.0 Degrees Leaf Angle (measure from 2nd leaf above 14.14 4 ear at anthesis to stalk above leaf) 03 Leaf Color  Dark Green (Munsell code)  5GY34 1.0 Leaf Sheath Pubescence (Rate on scale from 1= none to 9 = Iike peach fuzz) 4.5 Marginal Waves (Rate on scale from 1= none to 9 = many) 7.0 Longitudinal Creases (Rate on scale from 1 =none to 9 = many) 5. TASSEL: Standard Sample Deviation Size 02.7 Numberof Primary Lateral Branches 0.42 20 033.3 Branch Angle from CentralSpike 13.25  4 51.4 cm Tassel Length (from top leaf collar to tasseltip) 3.94  4 5.3 Pollen Shed (rate on scale from 0 = male sterile to 9 =heavy shed) 07 Anther Color  Yellow  (Munsell code)  5Y86 01 Glume Color Light Green  (Munsell code)  5GY66 1.0 Bar Glumes (Glume Bands): 1 =Absent 2 = Present 20 Peduncle Length (cm. from top leaf to basalbranches) 6a. EAR (Unhusked Data): 11 Silk Color (3 days afteremergence)  Pink  (Munsell code)  2.5R48 2 Fresh Husk Color (25 daysafter 50% silking)  Medium Green  (Munsell code)  5GY56 21 Dry HuskColor (65 days after 50% silking)  Buff  (Munsell code)  5Y92 1 Positionof Ear at Dry Husk Stage: 1 = Upright 2 = Horizontal 3 = Pendant Upright 5 Husk Tightness (Rate of Scale from 1 = very loose to 9 = verytight) 2 Husk Extension (at harvest): 1 = Short (ears exposed) 2 =Medium (<8 cm) 3 = Long (8-10 cm beyond ear tip) 4 = Very Long (>10 cm) Medium 6b. EAR (Husked Ear Data) Standard Sample Deviation Size 16 cmEar Length 0.58 20 39 mm Ear Diameter at mid-point 1.83 20 117 gm EarWeight 6.14 20 15 Number of Kernel Rows 0.96 20 2 Kernel Rows: 1 =Indistinct 2 = Distinct  Distinct 1 Row Alignment: 1 = Straight 2 =Slightly Curved 3 = Spiral  Straight 13 cm Shank Length 2.45 20 2 EarTaper: 1 = Slight 2 = Average 3 = Extreme  Average 7. KERNEL (Dried):Standard Sample Deviation Size 11 mm Kernel Length 0.50 20 7 mm KernelWidth 0.00 20 5 mm Kernel Thickness 0.50 20 18 % Round Kernels (ShapeGrade) 5.26  4 1 Aleurone Color Pattern: 1 = Homozygous 2 = Segregating Homozygous 16 Aluerone Color  Pale Purple  (Munsell code)  1.25Y812 7Hard Endosperm Color  Yellow  (Munsell code)  10YR712 3 Endosperm Type: Normal Starch 1 = Sweet (Su1) 2 = Extra Sweet (sh2) 3 = Normal Starch 4= High Amylose Starch 5 = Waxy Starch 6 = High Protein 7 = High Lysine 8= Super Sweet (se) 9 = High Oil 10 = Other_(———) 26 gm Weight per 100Kernels (unsized sample) 0.96  4 8. COB: Standard Sample Deviation Size22 mm Cob Diameter at mid-point 2.87 20 14 Cob Color  Red  (Munsellcode)  2.5YR3 9. DISEASE RESISTANCE (Rate from 1 (most susceptible) to 9(most resistant); leave blank if not tested; leave Race or StrainOptions blank if polygenic): A. Leaf Blights, Wilts, and Local InfectionDiseases Anthracnose Leaf Blight (Colletotrichum graminicola) 5 CommonRust (Puccinia sorghi) Common Smut (Ustilago maydis) 6 Eyespot(Kabatiella zeae) 8 Goss's Wilt (Clavibacter michiganense spp.nebraskense) 3 Gray Leaf Spot (Cercospora zeae-maydis) HelminthosporiumLeaf Spot (Bipolaris zeicola) Race_(——) 7 Northern Leaf Blight(Exserohilum turcicum) Race_(——) Southern Leaf Blight (Bipolaris maydis)Race_(——) Southern Rust (Puccinia polysora) Stewart's Wilt (Erwiniastewartii) Other (Specify)_(———) B. Systemic Diseases Corn LethalNecrosis (MCMV and MDMV) Head Smut (Sphacelotheca reiliana) MaizeChlorotic Dwarf Virus (MDV) Maize Chlorotic Mottle Virus (MCMV) MaizeDwarf Mosaic Virus (MDMV) Sorghum Downy Mildew of Corn(Peronosclerospora sorghi) Other (Specify)_(———) C. Stalk RotsAnthracnose Stalk Rot (Colletotrichum graminicola) Diplodia Stalk Rot(Stenocarpella maydis) Fusarium Stalk Rot (Fusarium moniliforme)Gibberella Stalk Rot (Gibberella zeae) Other (Specify)_(———) D. Ear andKernel Rots Aspergillus Ear and Kernel Rot (Aspergillus flavus) DiplodiaEar Rot (Stenocarpella maydis) Fusarium Ear and Kernel Rot (Fusariummoniliforme) 2 Gibberella Ear Rot (Gibberella zeae) Other(Specify)_(———) Banks grass Mite (Oligonychus pratensis) Corn Worm(Helicoverpa zea) Leaf Feeding Silk Feeding mg larval wt. Ear DamageCorn Leaf Aphid (Rhopalosiphum maidis) Corn Sap Beetle (Carpophilusdimidiatus European Corn Borer (Ostrinia nubilalis) 3 1st Generation(Typically Whorl Leaf Feeding) 2nd Generation (Typically LeafSheath-Collar Feeding) Stalk Tunneling cm tunneled/plant Fall Armyworm(Spodoptera fruqiperda) Leaf Feeding Silk Feeding mg larval wt. MaizeWeevil (Sitophilus zeamaize Northern Rootworm (Diabrotica barberi)Southern Rootworm (Diabrotica undecimpunctata) Southwestern Corn Borer(Diatreaea grandiosella) Leaf Feeding Stalk Tunneling cm tunneled/plantTwo-spotted Spider Mite (Tetranychus urticae) Western Rootworm(Diabrotica virgifrea virgifera) Other (Specify)_(———) 11. AGRONOMICTRAITS: 6 Staygreen (at 65 days after anthesis) (Rate on a scale from 1= worst to 9 = excellent) 1.2 % Dropped Ears (at 65 days after anthesis)% Pre-anthesis Brittle Snapping % Pre-anthesis Root Lodging 3.3Post-anthesis Root Lodging (at 65 days after anthesis) 4,073 Kg/ha Yield(at 12-13% grain moisture) *In interpreting the foregoing colordesignations, reference may be had to the Munsell Glossy Book of Color,a standard color reference.

FURTHER EMBODIMENTS OF THE INVENTION

This invention also is directed to methods for producing a maize plantby crossing a first parent maize plant with a second parent maize plantwherein either the first or second parent maize plant is an inbred maizeplant of the line PH45A. Further, both first and second parent maizeplants can come from the inbred maize line PH45A. Still further, thisinvention also is directed to methods for producing an inbred maize linePH45A-derived maize plant by crossing inbred maize line PH45A with asecond maize plant and growing the progeny seed, and repeating thecrossing and growing steps with the inbred maize line PH45A-derivedplant from 0 to 5 times. Thus, any such methods using the inbred maizeline PH45A are part of this invention: selfing, backcrosses, hybridproduction, crosses to populations, and the like. All plants producedusing inbred maize line PH45A as a parent are within the scope of thisinvention, including plants derived from inbred maize line PH45A.Advantageously, the inbred maize line is used in crosses with other,different, maize inbreds to produce first generation (F₁) maize hybridseeds and plants with superior characteristics.

It should be understood that the inbred can, through routinemanipulation of cytoplasmic or other factors, be produced in amale-sterile form. Such embodiments are also contemplated within thescope of the present claims.

As used herein, the term plant includes plant cells, plant protoplasts,plant cell tissue cultures from which maize plants can be regenerated,plant calli, plant clumps, and plant cells that are intact in plants orparts of plants, such as embryos, pollen, ovules, flowers, kernels,ears, cobs, leaves, husks, stalks, roots, root tips, anthers, silk andthe like.

Duncan, Williams, Zehr, and Widholm, Planta (1985) 165:322-332 reflectsthat 97% of the plants cultured that produced callus were capable ofplant regeneration. Subsequent experiments with both inbreds and hybridsproduced 91% regenerable callus that produced plants. In a further studyin 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988),7:262-265 reports several media additions that enhance regenerability ofcallus of two inbred lines. Other published reports also indicated that“nontraditional” tissues are capable of producing somatic embryogenesisand plant regeneration. K. P. Rao, et al., Maize Genetics CooperationNewsletter, 60:64-65 (1986), refers to somatic embryogenesis from glumecallus cultures and B. V. Conger, et al., Plant Cell Reports, 6:345-347(1987) indicates somatic embryogenesis from the tissue cultures of maizeleaf segments. Thus, it is clear from the literature that the state ofthe art is such that these methods of obtaining plants are, and were,“conventional” in the sense that they are routinely used and have a veryhigh rate of success.

Tissue culture of maize is described in European Patent Application,publication 160,390, incorporated herein by reference. Maize tissueculture procedures are also described in Green and Rhodes, “PlantRegeneration in Tissue Culture of Maize,” Maize for Biological Research(Plant Molecular Biology Association, Charlottesville, Va. 1982, at367-372) and in Duncan, et al., “The Production of Callus Capable ofPlant Regeneration from Immature Embryos of Numerous Zea MaysGenotypes,” 165 Planta 322-332 (1985). Thus, another aspect of thisinvention is to provide cells which upon growth and differentiationproduce maize plants having the physiological and morphologicalcharacteristics of inbred line PH45A.

The utility of inbred maize line PH45A also extends to crosses withother species. Commonly, suitable species will be of the familyGraminaceae, and especially of the genera Zea, Tripsacum, Coix,Schlerachne, Polytoca, Chionachne, and Trilobachne, of the tribeMaydeae. Potentially suitable for crosses with PH45A may be the variousvarieties of grain sorghum, Sorghum bicolor (L.) Moench.

Transformation of Maize

With the advent of molecular biological techniques that have allowed theisolation and characterization of genes that encode specific proteinproducts, scientists in the field of plant biology developed a stronginterest in engineering the genome of plants to contain and expressforeign genes, or additional, or modifed versions of native orendogenous genes (perhaps driven by different promoters) in order toalter the traits of a plant in a specific manner. Such foreign,additional and/or modified genes are referred to herein collectively as“transgenes”. Over the last fifteen to twenty years several methods forproducing transgenic plants have been developed, and the presentinvention, in particular embodiments, also relates to transformedversions of the claimed inbred maize line PH45A.

Plant transformation involves the construction of an expression vectorwhich will function in plant cells. Such a vector comprises DNAcomprising a gene under control of or operatively linked to a regulatoryelement (for example, a promoter). The expression vector may contain oneor more such operably linked gene/regulatory element combinations. Thevector(s) may be in the form of a plasmid, and can be used, alone or incombination with other plasmids, to provide transformed maize plants,using transformation methods as described below to incorporatetransgenes into the genetic material of the maize plant(s).

Expression Vectors For Maize Transformation

Marker Genes

Expression vectors include at least one genetic marker, operably linkedto a regulatory element (a promoter, for example) that allowstransformed cells containing the marker to be either recovered bynegative selection, i.e. inhibiting growth of cells that do not containthe selectable marker gene, or by positive selection, i.e., screeningfor the product encoded by the genetic marker. Many commonly usedselectable marker genes for plant transformation are well known in thetransformation arts, and include, for example, genes that code forenzymes that metabolically detoxify a selective chemical agent which maybe an antibiotic or a herbicide, or genes that encode an altered targetwhich is insensitive to the inhibitor. A few positive selection methodsare also known in the art.

One commonly used selectable marker gene for plant transformation is theneomycin phosphotransferase II (nptII) gene, isolated from transposonTn5, which when placed under the control of plant regulatory signalsconfers resistance to kanamycin. Fraley et al., Proc. Natl. Acad. Sci.U.S.A., 80 4803 (1983). Another commonly used selectable marker gene isthe hygromycin phosphotransferase gene which confers resistance to theantibiotic hygromycin. Vanden Elzen et al., Plant Mol. Biol., 5: 299(1985).

Additional selectable marker genes of bacterial origin that conferresistance to antibiotics include gentamycin acetyl transferase,streptomycin phosphotransferase, aminoglycoside-3′-adenyl transferase,the bleomycin resistance determinant. Hayford et al., Plant Physiol. 86:1216 (1988), Jones et al., Mol. Gen. Genet., 210: 86 (1987), Svab etal., Plant Mol. Biol. 14: 197 (1990), Hille et al., Plant Mol. Biol. 7:171 (1986). Other selectable marker genes confer resistance toherbicides such as glyphosate, glufosinate or broxynil. Comai et al.,Nature 317: 741-744 (1985), Gordon-Kamm et al., Plant Cell 2: 603-618(1990) and Stalker et al., Science 242: 419-423 (1988).

Other selectable marker genes for plant transformation are not ofbacterial origin. These genes include, for example, mouse dihydrofolatereductase, plant 5-enolpyruvylshikimate-3-phosphate synthase and plantacetolactate synthase. Eichholtz et al., Somatic Cell Mol. Genet. 13: 67(1987), Shah et al., Science 233: 478 (1986), Charest et al., Plant CellRep. 8: 643 (1990).

Another class of marker genes for plant transformation require screeningof presumptively transformed plant cells rather than direct geneticselection of transformed cells for resistance to a toxic substance suchas an antibiotic. These genes are particularly useful to quantify orvisualize the spatial pattern of expression of a gene in specifictissues and are frequently referred to as reporter genes because theycan be fused to a gene or gene regulatory sequence for the investigationof gene expression. Commonly used genes for screening presumptivelytransformed cells include β-glucuronidase (GUS), β-galactosidase,luciferase and chloramphenicol acetyltransferase. Jefferson, R. A.,Plant Mol. Biol. Rep. 5: 387 (1987)., Teeri et al., EMBO J. 8: 343(1989), Koncz et al., Proc. Natl. Acad. Sci. U.S.A. 84:131 (1987), DeBlock et al., EMBO J. 3: 1681 (1984). Another approach to theidentification of relatively rare transformation events has been use ofa gene that encodes a dominant constitutive regulator of the Zea maysanthocyanin pigmentation pathway. Ludwig et al., Science 247: 449(1990).

Recently, in vivo methods for visualizing GUS activity that do notrequire destruction of plant tissue have been made available. MolecularProbes Publication 2908, Imagene Green™, p. 1-4 (1993) and Naleway etal., J. Cell Biol. 115: 15Ia (1991). However, these in vivo methods forvisualizing GUS activity have not proven useful for recovery oftransformed cells because of low sensitivity, high fluorescentbackgrounds, and limitations associated with the use of luciferase genesas selectable markers.

More recently, a gene encoding Green Fluorescent Protein (GFP) has beenutilized as a marker for gene expression in prokaryotic and eukaryoticcells. Chalfie et al., Science 263: 802 (1994). GFP and mutants of GFPmay be used as screenable markers.

Promoters

Genes included in expression vectors must be driven by a nucleotidesequence comprising a regulatory element, for example, a promoter.Several types of promoters are now well known in the transformationarts, as are other regulatory elements that can be used alone or incombination with promoters.

As used herein “promoter” includes reference to a region of DNA upstreamfrom the start of transcription and involved in recognition and bindingof RNA polymerase and other proteins to initiate transcription. A “plantpromoter” is a promoter capable of initiating transcription in plantcells. Examples of promoters under developmental control includepromoters that preferentially initiate transcription in certain tissues,such as leaves, roots, seeds, fibers, xylem vessels, tracheids, orsclerenchyma. Such promoters are referred to as “tissue-preferred”.Promoters which initiate transcription only in certain tissues arereferred to as “tissue-specific”. A “cell type” specific promoterprimarily drives expression in certain cell types in one or more organs,for example, vascular cells in roots or leaves. An “inducible” promoteris a promoter which is under environmental control. Examples ofenvironmental conditions that may effect transcription by induciblepromoters include anaerobic conditions or the presence of light.Tissue-specific, tissue-preferred, cell type specific, and induciblepromoters constitute the class of “non-constitutive” promoters. A“constitutive” promoter is a promoter which is active under mostenvironmental conditions.

A. Inducible Promoters

An inducible promoter is operably linked to a gene for expression inmaize. Optionally, the inducible promoter is operably linked to anucleotide sequence encoding a signal sequence which is operably linkedto a gene for expression in maize. With an inducible promoter the rateof transcription increases in response to an inducing agent.

Any inducible promoter can be used in the instant invention. See Ward etal. Plant Mol. Biol.22: 361-366 (1993). Exemplary inducible promotersinclude, but are not limited to, that from the ACEI system whichresponds to copper (Mett et al. PNAS 90: 4567-4571 (1993)); In2 genefrom maize which responds to benzenesulfonamide herbicide safeners(Hershey et al., Mol. Gen. Genetics 227: 229-237 (1991) and Gatz et al.,Mol. Gen. Genetics 243: 32-38 (1994)) or Tet repressor from Tn10 (Gatzet al., Mol. Gen. Genet. 227: 229-237 (1991). A particularly preferredinducible promoter is a promoter that responds to an inducing agent towhich plants do not normally respond. An exemplary inducible promoter isthe inducible promoter from a steroid hormone gene, the transcriptionalactivity of which is induced by a glucocorticosteroid hormone. Schena etal., Proc. Natl. Acad. Sci. U.S.A. 88: 0421 (1991).

B. Constitutive Promoters

A constitutive promoter is operably linked to a gene for expression inmaize or the constitutive promoter is operably linked to a nucleotidesequence encoding a signal sequence which is operably linked to a genefor expression in maize.

Many different constitutive promoters can be utilized in the instantinvention. Exemplary constitutive promoters include, but are not limitedto, the promoters from plant viruses such as the 35S promoter from CaMV(Odell et al., Nature 313: 810-812 (1985) and the promoters from suchgenes as rice actin (McElroy et al., Plant Cell 2: 163-171 (1990));ubiquitin (Christensen et al., Plant Mol. Biol 12: 619-632 (1989) andChristensen et al., Plant Mol. Biol. 18: 675-689 (1992)): pEMU (Last etal., Theor. Appl. Genet. 81: 581-588 (1991)); MAS (Velten et al., EMBOJ. 3: 2723-2730 (1984)) and maize H3 histone (Lepetit et al., Mol. Gen.Genet. 231: 276-285 (1992) and Atanassova et al., Plant Journal 2 (3):291-300 (1992)).

The ALS promoter, a XbaI/NcoI fragment 5′ to the Brassica napus ALS3structural gene (or a nucleotide sequence that has substantial sequencesimilarity to said XbaI/NcoI fragment), represents a particularly usefulconstitutive promoter. See PCT application WO96/30530.

C. Tissue-specific or Tissue-Preferred Promoters

A tissue-specific promoter is operably linked to a gene for expressionin maize. Optionally, the tissue-specific promoter is operably linked toa nucleotide sequence encoding a signal sequence which is operablylinked to a gene for expression in maize. Plants transformed with a geneof interest operably linked to a tissue-specific promoter produce theprotein product of the transgene exclusively, or preferentially, in aspecific tissue.

Any tissue-specific or tissue-preferred promoter can be utilized in theinstant invention. Exemplary tissue-specific or tissue-preferredpromoters include, but are not limited to, a root-preferred promoter,such as that from the phaseolin gene (Murai et al., Science 23: 476-482(1983) and Sengupta-Gopalan et al., Proc. Natl. Acad. Sci. USA 82:3320-3324 (1985)); a leaf-specific and light-induced promoter such asthat from cab or rubisco (Simpson et al., EMBO J. 4(11): 2723-2729(1985) and Timko et al., Nature 318: 579-582 (1985)); an anther-specificpromoter such as that from LAT52 (Twell et al., Mol. Gen. Genet. 217:240-245 (1989)); a pollen-specific promoter such as that from Zm13(Guerrero et al., Mol. Gen. Genet.224: 161-168 (1993)) or amicrospore-preferred promoter such as that from apg (Twell et al., Sex.Plant Reprod. 6: 217-224 (1993).

Signal Sequences For Targeting Proteins to Subcellular Compartments

Transport of protein produced by transgenes to a subcellular compartmentsuch as the chloroplast, vacuole, peroxisome, glyoxysome, cell wall ormitochondrion, or for secretion into the apoplast, is accomplished bymeans of operably linking the nucleotide sequence encoding a signalsequence to the 5′ and/or 3′ region of a gene encoding the protein ofinterest. Targeting sequences at the 5′ and/or 3′ end of the structuralgene may determine, during protein synthesis and processing, where theencoded protein is ultimately compartmentalized. The presence of asignal sequence directs a polypeptide to either an intracellularorganelle or subcellular compartment or for secretion to the apoplast.Many signal sequences are known in the art. See, for example, Becker etal., Plant Mol. Biol.20: 49 (1992), Close, P. S., Master's Thesis, IowaState University (1993), Knox, C., et al., “Structure and Organizationof Two Divergent Alpha-Amylase Genes From Barley”, Plant Mol.Biol. 9:3-17 (1987), Lerner et al., Plant Physiol.91: 124-129 (1989), Fontes etal., Plant Cell 3: 483-496 (1991), Matsuoka et al., Proc. Natl. Acad.Sci. 88: 834 (1991), Gould et al., J. Cell Biol 108: 1657 (1989),Creissen et al., Plant J. 2: 129 (1991), Kalderon, D., Robers, B.,Richardson, W., and Smith A., “A short amino acid sequence able tospecify nuclear location”, Cell 39: 499-509 (1984), Stiefel, V.,Ruiz-Avila, L., Raz R., Valles M., Gomez J., Pages M.,Martinez-Izquierdo J., Ludevid M., Landale J., Nelson T., andPuigdomenech P., “Expression of a maize cell wall hydroxyproline-richglycoprotein gene in early leaf and root vascular differentiation”,Plant Cell 2: 785-793 (1990).

Foreign Protein Genes and Agronomic Genes

With transgenic plants according to the present invention, a foreignprotein can be produced in commercial quantities. Thus, techniques forthe selection and propagation of transformed plants, which are wellunderstood in the art, yield a plurality of transgenic plants which areharvested in a conventional manner, and a foreign protein then can beextracted from a tissue of interest or from total biomass. Proteinextraction from plant biomass can be accomplished by known methods whichare discussed, for example, by Heney and Orr, Anal. Biochem. 114: 92-6(1981).

According to a preferred embodiment, the transgenic plant provided forcommercial production of foreign protein is maize. In another preferredembodiment, the biomass of interest is seed. For the relatively smallnumber of transgenic plants that show higher levels of expression, agenetic map can be generated, primarily via conventional RestrictionFragment Length Polymorphisms (RFLP), Polymerase Chain Reaction (PCR)analysis, and Simple Sequence Repeats (SSR) which identifies theapproximate chromosomal location of the integrated DNA molecule. Forexemplary methodologies in this regard, see Glick and Thompson, METHODSIN PLANT MOLECULAR BIOLOGY AND BIOTECHNOLOGY 269-284 (CRC Press, BocaRaton, 1993). Map information concerning chromosomal location is usefulfor proprietary protection of a subject transgenic plant. Ifunauthorized propagation is undertaken and crosses made with othergermplasm, the map of the integration region can be compared to similarmaps for suspect plants, to determine if the latter have a commonparentage with the subject plant. Map comparisons would involvehybridizations, RFLP, PCR, SSR and sequencing, all of which areconventional techniques.

Likewise, by means of the present invention, agronomic genes can beexpressed in transformed plants. More particularly, plants can begenetically engineered to express various phenotypes of agronomicinterest. Exemplary genes implicated in this regard include, but are notlimited to, those categorized below.

1. Genes That Confer Resistance To Pests or Disease And That Encode:

(A) Plant disease resistance genes. Plant defenses are often activatedby specific interaction between the product of a disease resistance gene(R) in the plant and the product of a corresponding avirulence (Avr)gene in the pathogen. A plant variety can be transformed with clonedresistance gene to engineer plants that are resistant to specificpathogen strains. See, for example Jones et al., Science 266: 789 (1994)(cloning of the tomato Cf-9 gene for resistance to Cladosporium fulvum);Martin et al., Science 262: 1432 (1993) (tomato Pto gene for resistanceto Pseudomonas syringae pv. tomato encodes a protein kinase); Mindrinoset al., Cell 78: 1089 (1994) (Arabidopsis RSP2 gene for resistance toPseudomonas syringae).

(B) A Bacillus thuringiensis protein, a derivative thereof or asynthetic polypeptide modeled thereon. See, for example, Geiser et al.,Gene 48: 109 (1986), who disclose the cloning and nucleotide sequence ofa Bt δ-endotoxin gene. Moreover, DNA molecules encoding δ-endotoxingenes can be purchased from American Type Culture Collection (Rockville,Md.), for example, under ATCC Accession Nos. 40098, 67136, 31995 and31998.

(C) A lectin. See, for example, the disclosure by Van Damme et al.,Plant Molec. Biol. 24: 25 (1994), who disclose the nucleotide sequencesof several Clivia miniata mannose-binding lectin genes.

(D) A vitamin-binding protein such as avidin. See PCT applicationUS93/06487 the contents of which are hereby incorporated by. Theapplication teaches the use of avidin and avidin homologues aslarvicides against insect pests.

(E) An enzyme inhibitor, for example, a protease inhibitor or an amylaseinhibitor. See, for example, Abe et al., J. Biol. Chem. 262: 16793(1987) (nucleotide sequence of rice cysteine proteinase inhibitor), Huubet al., Plant Molec. Biol. 21: 985 (1993) (nucleotide sequence of cDNAencoding tobacco proteinase inhibitor I), and Sumitani et al., Biosci.Biotech. Biochem. 57: 1243 (1993) (nucleotide sequence of Streptomycesnitrosporeus α-amylase inhibitor).

(F) An insect-specific hormone or pheromone such as an ecdysteroid andjuvenile hormone, a variant thereof, a mimetic based thereon, or anantagonist or agonist thereof. See, for example, the disclosure byHammock et al., Nature 344: 458 (1990), of baculovirus expression ofcloned juvenile hormone esterase, an inactivator of juvenile hormone.

(G) An insect-specific peptide or neuropeptide which, upon expression,disrupts the physiology of the affected pest. For example, see thedisclosures of Regan, J. Biol. Chem. 269: 9 (1994) (expression cloningyields DNA coding for insect diuretic hormone receptor), and Pratt etal., Biochem. Biophys. Res. Comm.163: 1243 (1989) (an allostatin isidentified in Diploptera puntata). See also U.S. Pat. No. 5,266,317 toTomalski et al., who disclose genes encoding insect-specific, paralyticneurotoxins.

(H) An insect-specific venom produced in nature by a snake, a wasp, etc.For example, see Pang et al., Gene 116: 165 (1992), for disclosure ofheterologous expression in plants of a gene coding for a scorpioninsectotoxic peptide.

(I) An enzyme responsible for an hyperaccumulation of a monterpene, asesquiterpene, a steroid, hydroxamic acid, a phenylpropanoid derivativeor another non-protein molecule with insecticidal activity.

(J) An enzyme involved in the modification, including thepost-translational modification, of a biologically active molecule; forexample, a glycolytic enzyme, a proteolytic enzyme, a lipolytic enzyme,a nuclease, a cyclase, a transaminase, an esterase, a hydrolase, aphosphatase, a kinase, a phosphorylase, a polymerase, an elastase, achitinase and a glucanase, whether natural or synthetic. See PCTapplication WO 93/02197 in the name of Scott et al., which discloses thenucleotide sequence of a callase gene. DNA molecules which containchitinase-encoding sequences can be obtained, for example, from the ATCCunder Accession Nos. 39637 and 67152. See also Kramer et al., InsectBiochem. Molec. Biol.23: 691 (1993), who teach the nucleotide sequenceof a cDNA encoding tobacco hookworm chitinase, and Kawalleck et al.,Plant Molec. Biol. 21: 673 (1993), who provide the nucleotide sequenceof the parsley ubi4-2 polyubiquitin gene.

(K) A molecule that stimulates signal transduction. For example, see thedisclosure by Botella et al., Plant Molec. Biol. 24: 757 (1994), ofnucleotide sequences for mung bean calmodulin cDNA clones, and Griess etal., Plant Physiol.104: 1467 (1994), who provide the nucleotide sequenceof a maize calmodulin cDNA clone.

(L) A hydrophobic moment peptide. See PCT application WO95/16776(disclosure of peptide derivatives of Tachyplesin which inhibit fungalplant pathogens) and PCT application WO95/18855 (teaches syntheticantimicrobial peptides that confer disease resistance), the respectivecontents of which are hereby incorporated by reference.

(M) A membrane permease, a channel former or a channel blocker. Forexample, see the disclosure by Jaynes et al., Plant Sci. 89: 43 (1993),of heterologous expression of a cecropin-β lytic peptide analog torender transgenic tobacco plants resistant to Pseudomonas solanacearum.

(N) A viral-invasive protein or a complex toxin derived therefrom. Forexample, the accumulation of viral coat proteins in transformed plantcells imparts resistance to viral infection and/or disease developmenteffected by the virus from which the coat protein gene is derived, aswell as by related viruses. See Beachy et al., Ann. Rev. Phytopathol.28:451 (1990). Coat protein-mediated resistance has been conferred upontransformed plants against alfalfa mosaic virus, cucumber mosaic virus,tobacco streak virus, potato virus X, potato virus Y, tobacco etchvirus, tobacco rattle virus and tobacco mosaic virus. Id.

(O) An insect-specific antibody or an immunotoxin derived therefrom.Thus, an antibody targeted to a critical metabolic function in theinsect gut would inactivate an affected enzyme, killing the insect. Cf.Taylor et al., Abstract #497, SEVENTH INT'L SYMPOSIUM ON MOLECULARPLANT-MICROBE INTERACTIONS (Edinburgh, Scotland, 1994) (enzymaticinactivation in transgenic tobacco via production of single-chainantibody fragments).

(P) A virus-specific antibody. See, for example, Tavladoraki et al.,Nature 366: 469 (1993), who show that transgenic plants expressingrecombinant antibody genes are protected from virus attack.

(Q) A developmental-arrestive protein produced in nature by a pathogenor a parasite. Thus, fungal endo α-1,4-D-polygalacturonases facilitatefungal colonization and plant nutrient release by solubilizing plantcell wall homo-α-1,4-D-galacturonase. See Lamb et al., Bio/Technology10: 1436 (1992). The cloning and characterization of a gene whichencodes a bean endopolygalacturonase-inhibiting protein is described byToubart et al., Plant J. 2: 367 (1992).

(R) A developmental-arrestive protein produced in nature by a plant. Forexample, Logemann et al., Bio/Technology 10: 305 (1992), have shown thattransgenic plants expressing the barley ribosome-inactivating gene havean increased resistance to fungal disease.

2. Genes That Confer Resistance To A Herbicide, For Example:

(A) A herbicide that inhibits the growing point or meristem, such as animidazalinone or a sulfonylurea. Exemplary genes in this category codefor mutant ALS and AHAS enzyme as described, for example, by Lee et al.,EMBO J. 7: 1241 (1988), and Miki et al., Theor. Appl. Genet. 80: 449(1990), respectively.

(B) Glyphosate (resistance imparted by mutant5-enolpyruvl-3-phosphikimate synthase (EPSP) and aroA genes,respectively) and other phosphono compounds such as glufosinate(phosphinothricin acetyl transferase (PAT) and Streptomyceshygroscopicus phosphinothricin acetyl transferase (bar) genes), andpyridinoxy or phenoxy proprionic acids and cycloshexones (ACCaseinhibitor-encoding genes). See, for example, U.S. Pat. No. 4,940,835 toShah et al., which discloses the nucleotide sequence of a form of EPSPwhich can confer glyphosate resistance. A DNA molecule encoding a mutantaroA gene can be obtained under ATCC accession No. 39256, and thenucleotide sequence of the mutant gene is disclosed in U.S. Pat. No.4,769,061 to Comai. European patent application No. 0 333 033 to Kumadaet al. and U.S. Pat. No. 4,975,374 to Goodman et al. disclose nucleotidesequences of glutamine synthetase genes which confer resistance toherbicides such as L-phosphinothricin. The nucleotide sequence of aphosphinothricin-acetyl-transferase gene is provided in Europeanapplication No. 0 242 246 to Leemans et al. De Greef et al.,Bio/Technology 7: 61 (1989), describe the production of transgenicplants that express chimeric bar genes coding for phosphinothricinacetyl transferase activity. Exemplary of genes conferring resistance tophenoxy proprionic acids and cycloshexones, such as sethoxydim andhaloxyfop, are the Acc1-S1, Acc1-S2 and Acc1-S3 genes described byMarshall et al., Theor. Appl. Genet. 83: 435 (1992).

(C) A herbicide that inhibits photosynthesis, such as a triazine (psbAand gs+ genes) and a benzonitrile (nitrilase gene). Przibilla et al.,Plant Cell 3: 169 (1991), describe the transformation of Chlamydomonaswith plasmids encoding mutant psbA genes. Nucleotide sequences fornitrilase genes are disclosed in U.S. Pat. No. 4,810,648 to Stalker, andDNA molecules containing these genes are available under ATCC AccessionNos. 53435, 67441 and 67442. Cloning and expression of DNA coding for aglutathione S-transferase is described by Hayes et al., Biochem. J. 285:173 (1992).

3. Genes That Confer Or Contribute To A Value-Added Trait, Such As:

(A) Modified fatty acid metabolism, for example, by transforming a plantwith an antisense gene of stearoyl-ACP desaturase to increase stearicacid content of the plant. See Knultzon et al., Proc. Natl. Acad. Sci.USA 89: 2624 (1992).

(B) Decreased phytate content

(1) Introduction of a phytase-encoding gene would enhance breakdown ofphytate, adding more free phosphate to the transformed plant. Forexample, see Van Hartingsveldt et al., Gene 127: 87 (1993), for adisclosure of the nucleotide sequence of an Aspergillus niger phytasegene.

(2) A gene could be introduced that reduces phytate content. In maize,this, for example, could be accomplished, by cloning and thenreintroducing DNA associated with the single allele which is responsiblefor maize mutants characterized by low levels of phytic acid. See Raboyet al., Maydica 35: 383 (1990).

(C) Modified carbohydrate composition effected, for example, bytransforming plants with a gene coding for an enzyme that alters thebranching pattern of starch. See Shiroza et al., J. Bacteriol. 170: 810(1988) (nucleotide sequence of Streptococcus mutans fructosyltransferasegene), Steinmetz et al., Mol. Gen. Genet. 200: 220 (1985) (nucleotidesequence of Bacillus subtilis levansucrase gene), Pen et al.,Bio/Technology 10: 292 (1992) (production of transgenic plants thatexpress Bacillus licheniformis α-amylase), Elliot et al., Plant Molec.Biol. 21: 515 (1993) (nucleotide sequences of tomato invertase genes),Søgaard et al., J. Biol. Chem. 268: 22480 (1993) (site-directedmutagenesis of barley α-amylase gene), and Fisher et al., Plant Physiol.102: 1045 (1993) (maize endosperm starch branching enzyme II).

Methods for Maize Transformation

Numerous methods for plant transformation have been developed, includingbiological and physical, plant transformation protocols. See, forexample, Miki et al., “Procedures for Introducing Foreign DNA intoPlants” in Methods in Plant Molecular Biology and Biotechnology, Glick,B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages67-88. In addition, expression vectors and in vitro culture methods forplant cell or tissue transformation and regeneration of plants areavailable. See, for example, Gruber et al., “Vectors for PlantTransformation” in Methods in Plant Molecular Biology and Biotechnology,Glick, B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton,1993) pages 89-119.

A. Agrobacterium-mediated Transformation

One method for introducing an expression vector into plants is based onthe natural transformation system of Agrobacterium. See, for example,Horsch et al., Science 227: 1229 (1985). A. tumefaciens and A.rhizogenes are plant pathogenic soil bacteria which geneticallytransform plant cells. The Ti and Ri plasmids of A. tumefaciens and A.rhizogenes, respectively, carry genes responsible for genetictransformation of the plant. See, for example, Kado, C. I., Crit. Rev.Plant. Sci.10: 1 (1991). Descriptions of Agrobacterium vector systemsand methods for Agrobacterium-mediated gene transfer are provided byGruber et al., supra, Miki et al., supra, and Moloney et al., Plant CellReports 8: 238 (1989). See also, U.S. Pat. No. 5,591,616, issued Jan. 7,1997.

B. Direct Gene Transfer

Despite the fact the host range for Agrobacterium-mediatedtransformation is broad, some major cereal crop species and gymnospermshave generally been recalcitrant to this mode of gene transfer, eventhough some success has recently been achieved in rice and maize. Hieiet al., The Plant Journal 6: 271-282 (1994); U.S. Pat. No. 5,591,616,issued Jan. 7, 1997. Several methods of plant transformation,collectively referred to as direct gene transfer, have been developed asan alternative to Agrobacterium-mediated transformation.

A generally applicable method of plant transformation ismicroprojectile-mediated transformation wherein DNA is carried on thesurface of microprojectiles measuring 1 to 4 μm. The expression vectoris introduced into plant tissues with a biolistic device thataccelerates the microprojectiles to speeds of 300 to 600 m/s which issufficient to penetrate plant cell walls and membranes. Sanford et al.,Part. Sci. Technol. 5: 27 (1987), Sanford, J. C., Trends Biotech. 6: 299(1988), Klein et al., Bio/Technology 6: 559-563 (1988), Sanford, J. C.,Physiol Plant 79: 206 (1990), Klein et al., Biotechnology 10: 268(1992). In maize, several target tissues can be bombarded withDNA-coated microprojectiles in order to produce transgenic plants,including, for example, callus (Type I or Type II), immature embryos,and meristematic tissue.

Another method for physical delivery of DNA to plants is sonication oftarget cells. Zhang et al., Bio/Technology 9: 996 (1991). Alternatively,liposome or spheroplast fusion have been used to introduce expressionvectors into plants. Deshayes et al., EMBO J., 4: 2731 (1985), Christouet al., Proc Natl. Acad. Sci. U.S.A. 84: 3962 (1987). Direct uptake ofDNA into protoplasts using CaCl₂ precipitation, polyvinyl alcohol orpoly-L-ornithine have also been reported. Hain et al., Mol. Gen.Genet.199: 161 (1985) and Draper et al., Plant Cell Physiol.23: 451(1982). Electroporation of protoplasts and whole cells and tissues havealso been described. Donn et al., In Abstracts of VIIth InternationalCongress on Plant Cell and Tissue Culture IAPTC, A2-38, p 53 (1990);D'Halluin et al., Plant Cell 4: 1495-1505 (1992) and Spencer et al.,Plant Mol. Biol. 24: 51-61 (1994).

Following transformation of maize target tissues, expression of theabove-described selectable marker genes allows for preferentialselection of transformed cells, tissues and/or plants, usingregeneration and selection methods now well known in the art. Forexample, transformed maize immature embryos.

The foregoing methods for transformation would typically be used forproducing transgenic inbred lines. Transgenic inbred lines could then becrossed, with another (non-transformed or transformed) inbred line, inorder to produce a transgenic hybrid maize plant. Alternatively, agenetic trait which has been engineered into a particular maize lineusing the foregoing transformation techniques could be moved intoanother line using traditional backcrossing techniques that are wellknown in the plant breeding arts. For example, a backcrossing approachcould be used to move an engineered trait from a public, non-elite lineinto an elite line, or from a hybrid maize plant containing a foreigngene in its genome into a line or lines which do not contain that gene.As used herein, “crossing” can refer to a simple X by Y cross, or theprocess of backcrossing, depending on the context.

Industrial Applicability

Maize is used as human food, livestock feed, and as raw material inindustry. The food uses of maize, in addition to human consumption ofmaize kernels, include both products of dry- and wet-milling industries.The principal products of maize dry milling are grits, meal and flour.The maize wet-milling industry can provide maize starch, maize syrups,and dextrose for food use. Maize oil is recovered from maize germ, whichis a by-product of both dry- and wet-milling industries.

Maize, including both grain and non-grain portions of the plant, is alsoused extensively as livestock feed, primarily for beef cattle, dairycattle, hogs, and poultry.

Industrial uses of maize include production of ethanol, maize starch inthe wet-milling industry and maize flour in the dry-milling industry.The industrial applications of maize starch and flour are based onfunctional properties, such as viscosity, film formation, adhesiveproperties, and ability to suspend particles. The maize starch and flourhave application in the paper and textile industries. Other industrialuses include applications in adhesives, building materials, foundrybinders, laundry starches, explosives, oil-well muds, and other miningapplications.

Plant parts other than the grain of maize are also used in industry: forexample, stalks and husks are made into paper and wallboard and cobs areused for fuel and to make charcoal.

The seed of inbred maize line PH45A, the plant produced from the inbredseed, the hybrid maize plant produced from the crossing of the inbred,hybrid seed, and various parts of the hybrid maize plant and transgenicversions of the foregoing, can be utilized for human food, livestockfeed, and as a raw material in industry.

Performance Examples of PH45A

In the examples that follow, the traits and characteristics of inbredmaize line PH45A are given as a line. The data collected on inbred maizeline PH45A is presented for the key characteristics and traits.

Inbred Comparisons

The results in Table 2A compare inbred PH45A and inbred PH38D. Theresults show inbred PH45A demonstrates significantly higher yields withsignificantly lower harvest moisture and significantly higher testweight than inbred PH38D. Inbred PH45A flowers (GDU SHD and GDU SLK)significantly earlier than inbred PH38D. Inbred PH45A shows good staygreen scores.

The results in Table 2B compare inbred PH45A and inbred PHAA0. Theresults show that while inbred PH45A demonstrates significantly loweryields, inbred PH45A does show significantly higher test weight thaninbred PHAA0. Inbred PH45A exhibits good seedling vigor and exhibitssignificantly higher early stand counts than inbred PHAA0. Inbred PH45Ashows significantly better stay green scores than inbred PHAA0.

The results in Table 2C compare inbred PH45A and inbred PHRE1. Theresults show inbred PH45A demonstrates significantly higher yields thaninbred PHRE1. Inbred PH45A presents a significantly taller plant withsignificantly higher ear placement than inbred PHRE1. Inbred PH45Aexhibits significantly better resistance to root lodging than inbredPHRE1. Inbred PH45A shows significantly better stay green scores thaninbred PHRE1.

Inbred by Tester Comparisons

The results in Table 3A compare the inbred PH45A and inbred PH38D, wheneach inbred is crossed to the same tester lines. The PH45A hybrids showabove average yields and demonstrate significantly lower harvestmoisture and significantly higher test weight than the PH38D hybrids.The PH45A hybrids also show significantly better seedling vigor than thePH38D hybrids. The PH45A hybrids flower (GDU SHD and GDU SLK)significantly earlier than the PH38D hybrids. The PH45A hybrids showabove average and significantly better stay green scores than the PH38Dhybrids.

The results in Table 3B compare the inbred PH45A and inbred PHAA0, wheneach inbred is crossed to the same tester lines. The PH45A hybrids showgood yields and show significantly higher test weight than the PHAA0hybrids. Inbred PH45A exhibits good seedling vigor and exhibits aboveaverage early stand counts. The PH45A hybrids show significantly betterstay green scores and above average and significantly better resistanceto stalk lodging than the PHAA0 hybrids.

The results in Table 3C compare the inbred PH45A and inbred PHRE1, wheneach inbred is crossed to the same tester lines. The PH45A hybrids showgood yields. Inbred PH45A exhibits above average seedling vigor andexhibits above average early stand counts. The PH45A hybrids showsignificantly better stay green scores and present a significantlytaller plant than the PHRE1 hybrids.

Hybrid Comparisons

The results in Table 4A compare inbred PH45A crossed to inbred PH24E andinbred PH38D crossed to inbred PH24E. The results show that while thePH38D/PH24E hybrid demonstrates a significantly higher yield than thePH45A/PH24E hybrid, the PH45A/PH24E hybrid shows significantly lowerharvest moisture and significantly higher test weight. The PH45A/PH24Ehybrid exhibits significantly better seedling vigor and flowers (GDU SHDand GDU SLK) significantly earlier than the PH38D/PH24E hybrid. ThePH45A/PH24E hybrid shows significantly better stay green scores than thePH38D/PH24E hybrid.

The results in Table 4B compare inbred PH45A crossed to inbred PH24E andinbred PHRE1 crossed to inbred PHP02. The results the PH45A/PH24E hybriddemonstrates an above average and significantly higher yield andsignificantly higher test weight than the PHRE1/PHP02 hybrid. ThePH45A/PH24E hybrid flowers earlier than average and exhibits aboveaverage early stand count. The PH45A/PH24E hybrid presents asignificantly taller plant than the PHRE1/PHP02 hybrid. The PH45A/PH24Ehybrid shows significantly better stay green scores than the PHRE1/PHP02hybrid.

TABLE 2A PAIRED INBRED COMPARISON REPORT VARIETY #1 = PH45A VARIETY #2 =PH38D BU BU TST SDG EST TIL GDU GDU ACR ACR MST WT VGR CNT LER SHD SLKABS % MN ABS ABS ABS ABS ABS ABS ABS TOTAL SUM 1 65.3 97 21.6 57.6 5.336.1 2.7 122.4 123.3 2 59.0 89 22.8 55.9 5.3 37.1 1.4 138.2 138.9 LOCS54 54 59 32 52 91 49 83 78 REPS 60 60 65 38 53 110 52 83 80 DIFF 6.3 81.2 1.6 0.0 1.0 1.3 15.8 15.6 PR > T .012+ .031+ .037+ .000# .999 .116.303 .000# .000# POL TAS PLT EAR RT STA STK BRT GRN SC SZ HT HT LDG GRNLDG STK APP ABS ABS ABS ABS ABS ABS ABS ABS ABS TOTAL SUM 1 4.1 3.9 76.228.9 96.5 5.6 96.7 93.1 7.4 2 4.7 3.4 84.5 29.9 94.0 5.4 96.2 93.8 6.9LOCS 12 39 52 43 22 18 21 12 11 REPS 12 39 54 46 23 18 24 13 12 DIFF 0.60.5 8.3 1.0 2.6 0.2 0.5 0.8 0.5 PR > T .152 .065* .000# .239 .325 .521.804 .732 .085# SCT EAR TEX EAR BAR DRP GLF NLF EYE GRN SZ EAR MLD PLTEAR SPT BLT SPT ABS ABS ABS ABS ABS ABS ABS ABS ABS TOTAL SUM 1 7.1 4.36.7 7.6 93.0 98.8 3.0 8.0 6.0 2 6.7 5.3 7.3 7.5 94.2 99. 1 4.0 7.5 8.0LOCS 12 3 7 13 40 14 1 2 1 REPS 12 3 7 13 42 17 1 2 1 DIFF 0.4 1.0 0.60.2 1.2 0.3 1.0 0.5 2.0 PR > T .558 .423 .103 .673 .362 .497 .500 COMECB RST 1LF ABS ABS TOTAL SUM 1 4.6 3.5 2 4.0 5.0 LOCS 5 2 REPS 5 2 DIFF0.6 1.5 PR > T .426 .500 * = 10% SIG + = 5% SIG # = 1% SIG

TABLE 2B PAIRED INBRED COMPARISON REPORT VARIETY #1 = PH45A VARIETY #2 =PHAA0 BU BU TST SDG EST TIL GDU GDU ACR ACR MST WT VGR CNT LER SHD SLKABS % MN ABS ABS ABS ABS ABS ABS ABS TOTAL SUM 1 65.7 97 21.6 57.6 5.237.3 2.1 119.5 120.2 2 75.4 112 18.9 56.6 5.4 35.5 1.7 116.8 118.0 LOCS54 54 60 33 60 110 67 115 111 REPS 59 59 66 39 61 117 70 115 113 DIFF9.7 14 2.7 1.0 0.2 1.8 0.3 2.7 2.2 PR > T .000# .000# .000# .010+ .226.024+ .722 .000# .000# POL TAS TAS PLT EAR RT STA STK BRT SC BLS SZ HTHT LDG GRN LDG STK ABS ABS ABS ABS ABS ABS ABS ABS ABS TOTAL SUM 1 4.49.0 4.0 75.4 28.5 96.4 5.7 96.4 93.1 2 4.1 9.0 3.6 72.1 29.0 95.4 3.895.3 97.7 LOCS 16 1 48 66 53 21 18 19 12 REPS 16 1 48 69 56 22 18 22 13DIFF 0.3 0.0 0.4 3.2 0.4 1.0 1.9 1.0 4.6 PR > T .173 .017+ .000# .563.604 .001# .584 .023+ GRN SCT EAR TEX EAR BAR DRP GLF NLF APP GRN SZ EARMLD PLT EAR SPT BLT ABS ABS ABS ABS ABS ABS ABS ABS ABS TOTAL SUM 1 7.47.2 4.8 6.7 7.5 93.4 98.7 3.3 7.3 2 6.8 7.6 5.8 5.6 7.8 98.3 97.5 2.86.6 LOCS 11 15 5 9 14 43 13 2 6 REPS 12 15 5 9 14 45 16 3 9 DIFF 0.6 0.41.0 1.1 0.3 4.9 1.1 0.5 0.8 PR > T .005# .334 .230 .001# .365 .001#.044+ .500 .151 GOS HD GIB EYE COM ECB WLT SMT ERS SPT RST 1LF ABS ABSABS ABS ABS ABS TOTAL SUM 1 8.3 97.4 1.9 6.0 4.6 3.0 2 8.3 97.5 2.5 6.34.9 4.2 LOCS 2 8 4 2 5 3 REPS 4 23 8 3 5 3 DIFF 0.0 0.1 0.6 0.3 0.3 1.2PR > T .999 .911 .342 .795 .692 .369 * = 10% SIG + = 5% SIG # = 1% SIG

TABLE 2C PAIRED INBRED COMPARISON REPORT VARIETY #1 = PH45A VARIETY #2 =PHRE1 BU BU TST SDG EST TIL GDU GDU ACR ACR MST WT VGR CNT LER SHD SLKABS % MN ABS ABS ABS ABS ABS ABS ABS TOTAL SUM 1 65.2 96 21.2 57.6 5.336.9 2.1 117.9 118.7 2 58.2 85 18.2 57.8 5.8 36.6 2.0 113.7 113.7 LOCS62 62 68 33 59 112 66 128 122 REPS 76 76 82 39 60 130 71 138 132 DIFF7.0 12 2.9 0.3 0.5 0.3 0.1 4.1 5.0 PR > T .004# .002# .000# .565 .006#.697 .945 .000# .000# POL POL POL TAS TAB PLT EAR RT STA WT WT SC BLS SZHT HT LDG GRN ABS % MN ABS ABS ABS ABS ABS ABS ABS TOTAL SUM 1 76.7 654.4 9.0 4.0 75.7 28.5 96.5 5.7 2 93.0 77 4.6 9.0 4.4 61.9 26.4 75.8 3.7LOCS 16 16 16 1 48 64 53 22 18 REPS 22 22 16 1 48 67 56 23 18 DIFF 16.312 0.3 0.0 0.4 13.8 2.1 20.7 2.0 PR > T .117 .156 .362 .022+ .000# .003#.001# .001# STK BRT GRN SCT EAR TEX EAR BAR DRP LDG STK APP GRN SZ EARMLD PLT EAR ABS ABS ABS ABS ABS ABS ABS ABS ABS TOTAL SUM 1 96.6 93.17.4 7.5 4.8 6.7 7.5 93.6 98.8 2 93.8 95.1 7.4 7.1 4.5 4.5 7.2 97.0 99.4LOCS 20 12 11 14 5 9 14 44 14 REPS 23 13 12 14 5 9 14 48 17 DIFF 2.7 2.00.0 0.4 0.3 2.2 0.3 3.4 0.6 PR > T .187 .156 .999 .239 .529 .000# .513.000# .148 GLF NLF GOS HD GIB EYE COM ECB SPT BLT WLT SMT ERS SPT RST1LF ABS ABS ABS ABS ABS ABS ABS ABS TOTAL SUM 1 3.3 7.3 8.3 97.4 1.9 6.04.6 3.0 2 3.5 7.7 8.5 99.4 4.1 6.0 6.6 3.3 LOCS 2 6 2 8 4 2 5 3 REPS 3 94 23 8 3 5 3 DIFF 0.3 0.3 0.3 2.0 2.3 0.0 2.0 0.3 PR > T .874 .530 .500.181 .149 .999 .089* .423 * = 10% SIG + = 5% SIG # = 1% SIG

TABLE 3A Average Inbred By Tester Performance Comparing PH45A To PH38DCrossed To The Same Inbred Testers And Grown In The Same Experiments.SEL BU BU PRM TST SDG EST GDU IND PRM ACR ACR SHD MST WT VGR CNT SHD %MN ABS ABS % MN ABS % MN ABS % MN % MN % MN TOTAL SUM REPS 1 6 248 248 6251 26 117 142 79 LOCS 1 6 248 248 6 251 26 117 142 79 PH45A 102 104 163101 101 98 54 103 101 96 PH38D 106 105 169 105 106 101 53 95 100 102DIFF 3 1 6 3 5 3 1 8 1 5 PR > T 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.360.00 GDU STK PLT EAR RT STA STK BRT GRN GOS SLK CNT HT HT LDG GRN LDGSTK APP WLT % MN % MN % MN % MN % MN % MN % MN % MN % MN ABS TOTAL SUMREPS 38 278 111 111 78 100 157 23 10 1 LOCS 38 278 111 111 78 100 157 2310 1 PH45A 96 101 96 96 103 111 105 102 110 8 PH38D 101 100 98 96 102103 105 102 102 8 DIFF 6 1 3 1 0 8 0 0 8 0 PR > T 0.00 0.03 0.00 0.670.99 0.02 0.99 0.99 0.02 0.99 STW HD FUS COM ECB ECB ECB DRP GLF NLF WLTSMT ERS RST DPE 1LF 2SC EAR SPT BLT ABS ABS ABS ABS ABS ABS ABS % MN ABSABS TOTAL SUM REPS 1 1 1 1 5 1 12 120 14 4 LOCS 1 1 1 1 5 1 12 120 14 4PH45A 6 100 5 7 63 2 6 100 4 7 PH38D 6 98 8 8 59 4 5 100 4 7 DIFF 0 2 31 4 2 1 1 0 0 PR > T 0.99 0.33 0.00 0.06 0.99 0.99 *PR >T values arevalid only for comparisons with Locs >= 10.

TABLE 3B Average Inbred By Tester Performance Comparing PH45A To PHAA0Crossed To The Same Inbred Testers And Grown In The Same Experiments.SEL BU BU PRM TST SDG EST GDU IND PRM ACR ACR SHD MST WT VGR CNT SHD %MN ABS ABS % MN ABS % MN ABS % MN % MN % MN TOTAL SUM REPS 6 8 32 32 453 26 30 33 17 LOCS 6 8 26 26 4 45 20 26 26 12 PH45A 99 91 145 100 91101 55 95 104 100 PHAA0 103 B9 147 101 88 97 54 98 102 98 DIFF 4 2 2 1 24 1 3 1 2 PR > T 0.16 0.01 0.55 0.54 0.02 0.00 0.00 0.49 0.37 0.01 GDUSTK PLT EAR RT STA STK BRT GRN EYE SLK CNT HT HT LDG GRN LDG STK APP SPT% MN % MN % MN % MN % MN % MN % MN % MN % MN ABS TOTAL SUM REPS 12 55 1212 26 17 36 11 2 1 LOCS 10 47 9 9 21 14 31 8 2 1 PH45A 102 101 99 100105 110 102 98 97 7 PHAA0 99 101 98 98 107 88 96 94 87 4 DIFF 3 0 1 2 222 5 4 10 3 PR > T 0.00 0.99 0.26 0.70 0.30 0.02 0.00 0.29 0.50 DRP EAR% MN TOTAL SUM REPS 11 LOCS 11 PH45A 100 PHAA0 100 DIFF 0 PR > T 0.99*PR > T values are valid only for comparisons with Locs >= 10.

TABLE 3C Average Inbred By Tester Performance Comparing PH45A To PHRE1Crossed To The Same Inbred Testers And Grown In The Same Experiments.SEL BU BU PRM TST SDG EST GDU IND PRM ACR ACR SHD MST WT VGR CNT SHD %MN ABS ABS % MN ABS % MN ABS % MN % MN % MN TOTAL SUM REPS 9 11 51 51 772 34 33 43 19 LOCS 9 11 47 47 7 65 31 32 37 15 PH45A 99 96 135 100 96103 53 104 102 101 PHRE1 107 92 140 105 93 95 53 100 101 99 DIFF 8 4 5 53 9 0 4 0 2 PR > T 0.03 0.00 0.05 0.02 0.03 0.00 0.99 0.39 0.99 0.00 GDUSTK PLT EAR RT STA STK BRT GRN EYE SLK CNT HT HT LDG GRN LDG STK APP SPT% MN % MN % MN % MN % MN % MN % MN % MN % MN ABS TOTAL SUM REPS 10 76 2424 20 21 53 9 12 1 LOCS 9 69 23 23 17 19 49 9 12 1 PH45A 100 100 101 102102 122 105 99 103 7 PHRE1 97 101 98 106 103 82 102 97 96 5 DIFF 3 1 4 42 40 3 1 6 2 PR > T 0.05 0.05 0.01 0.05 0.17 0.00 0.10 0.51 0.13 COM ECBDRP RST DPE EAR ABS ABS % MN TOTAL SUM REPS 1 2 29 LOCS 1 2 29 PH45A 2100 100 PHRE1 7 100 100 DIFF 5 0 0 PR > T 0.99 0.99 *PR > T values arevalid only for comparisons with Locs >= 10.

TABLE 4A INBREDS IN HYBRID COMBINATION REPORT VARIETY #1 = PH45A/PH24EVARIETY #2 = PH38D/PH24E PRM BU BU TST SDG EST GDU PRM SHD ACR ACR MSTWT VGR CNT SHD ABS ABS ABS % MN % MN ABS % MN % MN % MN TOTAL SUM 1 10399 162.2 100 97 55.1 102 101 96 2 104 106 169.0 104 101 54.4 95 100 101LOCS 19 22 167 167 171 73 88 88 61 REPS 19 22 196 196 193 75 99 94 73DIFF 1 6 6.8 4 4 0.6 7 1 5 PR > T .001# .000# .000# .000# .000# .019+.016+ .686 .000# GDU STK PLT EAR RT STA STK BRT GRN SLK CNT HT HT LDGGRN LDG STK APP % MN % MN % MN % MN % MN % MN % MN % MN % MN TOTAL SUM 195 100 96 97 101 107 104 104 110 2 101 100 97 94 101 94 103 103 102 LOCS35 195 73 73 55 71 108 23 10 REPS 41 248 88 88 66 85 125 31 10 DIFF 6 12 2 0 13 1 2 8 PR > T .000# .334 .201 .044+ .999 .001# .674 .426 .015+DRP GLF NLF GOS STW ANT HD FUS GI8 EAR SPT BLT WLT WLT ROT SMT ERS ERS %MN ABS ABS ABS ABS ABS ABS ABS ABS TOTAL SUM 1 100 3.7 6.8 8.0 6.0 5.098.8 3.8 4.0 2 100 4.2 6.6 8.0 6.0 4.5 97.7 5.5 6.3 LOCS 66 9 7 1 1 1 22 2 REPS 66 13 13 1 1 2 6 3 4 DIFF 1 0.5 0.1 0.0 0.0 0.5 1.0 1.8 2.3PR > T .173 .135 .631 .551 .395 .070* DIP COM ECB ECB ECB ERS RST DPE1LF 2SC ABS ABS ABS ABS ABS TOTAL SUM 1 4.0 7.0 63.2 2.7 5.4 2 2.5 8.059.3 4.2 4.8 LOCS 1 1 5 6 12 REPS 2 1 10 6 15 DIFF 1.5 1.0 3.9 1.5 0.5PR > T .327 .007# .245 * = 10% SIG + = 5% SIG # = 1% SIG

TABLE 4B INBREDS IN HYBRID COMBINATION REPORT VARIETY #1 = PH45A/PH24EVARIETY #2 = PHRE1/PHP02 PRM BU BU TST SDG EST GDU PRM SHD ACR ACR MSTWT VGR CNT SHD ABS ABS ABS % MN % MN ABS % MN % MN % MN TOTAL SUM 1 10199 157.8 102 103 53.1 97 103 97 2 99 96 138.6 89 89 52.2 97 98 95 LOCS 34 14 14 14 8 11 9 4 REPS 3 4 14 14 14 8 11 9 4 DIFF 2 3 19.2 13 14 0.8 06 2 PR > T .093* .067* .000# .000# .000# .050* .999 .149 .068* GDU STKPLT EAR RT STA STK BRT DRP SLK CNT HT HT LDG GRN LDG STK EAR % MN % MN %MN % MN % MN % MN % MN % MN % MN TOTAL SUM 1 98 102 98 96 104 122 101115 100 2 94 100 95 98 102 64 97 82 98 LOCS 2 17 7 7 5 11 9 2 9 REPS 225 7 7 5 11 9 2 9 DIFF 4 2 3 3 2 58 4 33 3 PR > T .020+ .347 .026+ .325.489 .000# .176 .500 .066* NLF ECB ECB BLT DPE 2SC ABS ABS ABS TOTAL SUM1 7.0 100.0 6.0 2 6.0 100.0 2.0 LOCS 2 3 1 REPS 2 3 1 DIFF 1.0 0.0 4.0PR > T .000# .999 * = 10% SIG + = 5% SIG # = 1% SIG

Deposits

A deposit of the seed of inbred PH45A is and has been maintained byPioneer Hi-Bred International, Inc., 700 Capital Square, 400 LocustStreet, Des Moines, Iowa 50309-2340, since prior to the filing date ofthis application. Access to this deposit will be available during thependency of the application to the Commissioner of Patents andTrademarks and person determined by the Commissioner to be entitledthereto upon request. Upon allowance of any claims in the application,the Applicant(s) will make available to the public without restriction adeposit of at least 2500 seeds of inbred PH45A with the American TypeCulture Collection (ATCC), Rockville, Md., 20852. The seeds depositedwith the ATCC will be taken from the same deposit maintained at PioneerHi-Bred and described above. Additionally, Applicant(s) will meet allthe requirements of 37 C.F.R. §1.801-1.809, including providing anindication of the viability of the sample when the deposit is made. Thisdeposit of Inbred Maize Line PH45A will be maintained in the ATCCDepository, which is a public depository, for a period of 30 years, or 5years after the most recent request, or for the enforceable life of thepatent, whichever is longer, and will be replaced if it ever becomesnonviable during that period. Applicant will impose no restrictions onthe availability of the deposited material from the ATCC; however,Applicant has no authority to waive any restrictions imposed by law onthe transfer of biological material or its transportation in commerce.Applicant does not waive any infringement of its rights granted underthis patent or under the Plant Variety Protection Act (7 USC 2321 etseq.).

The foregoing invention has been described in detail by way ofillustration and example for purposes of clarity and understanding.However, it will be obvious that certain changes and modifications suchas single gene modifications and mutations, somoclonal variants, variantindividuals selected from large populations of the plants of the instantinbred and the like may be practiced within the scope of the invention,as limited only by the scope of the appended claims.

What is claimed is:
 1. Seed of maize inbred line designated PH45A,representative samples having been deposited under ATCC Accession No.PTA-2122.
 2. A maize plant, or parts thereof, having all thephysiological and morphological characteristics of inbred line PH45A,representative seed of said line having been deposited under ATCCaccession No. PTA-2122.
 3. The maize plant of claim 2, wherein saidplant is male sterile.
 4. A tissue culture of regenerable cells of amaize plant of inbred line PH45A, representative seed of which have beendeposited under ATCC Accession No. PTA-2122, wherein the tissueregenerates plants capable of expressing all the morphological andphysiological characteristics of the inbred line PH45A.
 5. A tissueculture according to claim 4, the cells or protoplasts being from atissue selected from the group consisting of leaves, pollen, embryos,roots, root tips, anthers, silks, flowers, kernels, ears, cobs, husks,and stalks.
 6. A maize plant regenerated from the tissue culture ofclaim 4, capable of expressing all the morphological and physiologicalcharacteristics of inbred line PH45A, representative seed of which havebeen deposited under ATCC Accession No. PTA-2122.
 7. A method forproducing a first generation (F₁) hybrid maize seed comprising crossingthe plant of claim 2 with a different inbred parent maize plant andharvesting the resultant first generation (F₁) hybrid maize seed.
 8. Themethod of claim 7 wherein inbred maize plant of claim 2 is the female ormale parent.
 9. An F₁ hybrid seed produced by crossing the inbred maizeplant according to claim 2 with another, different maize plant.
 10. AnF₁ hybrid plant, or parts thereof, grown from the seed of claim
 9. 11. Aprocess for producing inbred PH45A, representative seed of which havebeen deposited under ATCC Accession No. PTA-2122, comprising: (a)planting a collection of seed comprising seed of a hybrid, one of whoseparents is Inbred PH45A said collection also comprising seed of saidinbred; (b) growing plants from said collection of seed; (c) identifyinginbred parent plants; (d) selecting said inbred parent plant; (e)controlling pollination in a manner which preserves the homozygosity ofsaid inbred parent plant; and (f) collecting morphological and/orphysiological data so that said inbred parent may be identified asinbred PH45A.
 12. The process of claim 11 wherein step (c) comprisesidentifying plants with decreased vigor.
 13. The process of claim 11wherein step (c) comprises identifying seeds or plants with homozygousgenotype.
 14. A method for producing a PH45A-derived maize plant,comprising: (a) crossing inbred maize line PH45A, representative seed ofsaid line having been deposited under ATCC accession No. PTA-2122, witha second maize plant to yield progeny maize seed; (b) growing saidprogeny maize seed, under plant growth conditions, to yield saidPH45A-derived maize plant.
 15. A PH45A-derived maize plant, or partsthereof, produced by the method of claim 14, said PH45A-derived maizeplant expressing a combination of at least two PH45A traits selectedfrom the group consisting of: a relative maturity of approximately 97based on the Comparative Relative Maturity Rating System for harvestmoisture of grain, high yield, early flowering, good stay green andadapted to the Central Corn Belt, Northwest, Northcentral and Northeastregions of the United States.
 16. The method of claim 14, furthercomprising: (c) crossing said PH45A-derived maize plant with itself oranother maize plant to yield additional PH45A-derived progeny maizeseed; (d) growing said progeny maize seed of step (c) under plant growthconditions, to yield additional PH45A-derived maize plants; (e)repeating the crossing and growing steps of (c) and (d) from 0 to 4times to generate further PH45A-derived maize plants, wherein saidfurther PH45A-derived maize plants express traits genetically derivedfrom inbred PH45A.
 17. A further PH45A-derived maize plant, or partsthereof, produced by the method of claim
 16. 18. The method of claim 14,still further comprising utilizing plant tissue culture methods toderive progeny of said PH45A-derived maize plant.
 19. A PH45A-derivedmaize plant, or parts thereof, produced by the method of claim 18, saidPH45A-derived maize plant expressing a combination of at least two PH45Atraits selected from the group consisting of: a relative maturity ofapproximately 97 based on the Comparative Relative Maturity RatingSystem for harvest moisture of grain, high yield, early flowering, goodstay green and adapted to the Central Corn Belt, Northwest, Northcentraland Northeast regions of the United States.
 20. The maize plant, orparts thereof, of claim 2, wherein the plant or parts thereof have beentransformed so that its genetic material contains one or more transgenesoperably linked to one or more regulatory elements.
 21. A method forproducing a maize plant that contains in its genetic material one ormore transgenes, comprising crossing the maize plant of claim 20 witheither a second plant of another maize line, or a non-transformed maizeplant of the line PH45A, so that the genetic material of the progenythat result from the cross contains the transgene(s) operably linked toa regulatory element.
 22. Maize plants, or parts thereof, produced bythe method of claim
 21. 23. A maize plant, or parts thereof, wherein atleast one ancestor of said maize plant is the maize plant of claim 2,said maize plant expressing a combination of at least two PH45A traitsselected from the group consisting of: a relative maturity ofapproximately 97 based on the Comparative Relative Maturity RatingSystem for harvest moisture of grain, high yield, early flowering, goodstay green and adapted to the Central Corn Belt, Northwest, Northcentraland Northeast regions of the United States.
 24. A method for developinga maize plant in a maize plant breeding program using plant breedingtechniques, which include employing a maize plant, or its parts, as asource of plant breeding material, comprising: using the maize plant, orits parts, of claim 2 as a source of said breeding material.
 25. Themaize plant breeding program of claim 24 wherein plant breedingtechniques are selected from the group consisting of: recurrentselection, backcrossing, pedigree breeding, restriction fragment lengthpolymorphism enhanced selection, genetic marker enhanced selection, andtransformation.
 26. A maize plant, or parts thereof, produced by themethod of claim
 24. 27. The further PH45A-derived maize plant, or partsthereof, of claim 17, wherein said further PH45A-derived maize plant, orparts thereof, express a combination of at least two PH45A traitsselected from the group consisting of: a relative maturity ofapproximately 97 based on the Comparative Relative Maturity RatingSystem for harvest moisture of grain, high yield, early flowering, goodstay green and adapted to the Central Corn Belt, Northwest, Northcentraland Northeast regions of the United States.